1. Field of the Invention
The present invention relates to a clutch disc and in particular to a clutch disc having integral friction material included therewith and a pair of axially oppositely facing friction surfaces.
2. Description of the Art
A conventional clutch disc is disclosed in U.S. Pat. No. 4,646,900. In the conventional clutch disc, a circular plate or clutch plate is mounted on a hub. At an outer periphery, the circular plate is provided with a plurality of equally pitched blades which project outwardly in a radial direction. For connecting the circular plate and an integral annulus of friction material, one friction surface thereof is provided with a plurality of equally spaced grooves, each of which extends in the radial direction. Each of the plurality of equally pitched blades is fitted in and bonded to a corresponding radial groove.
However, a predetermined time is required for drying after application of a bonding substance between the blade and the groove in the assembly process of the conventional clutch disc. Further, since the bonding strength between the blade of the circular plate and the groove of the friction material may vary in accordance with ambient conditions, such as temperature, the friction material is subject to removal or other displacement from the circular plate during rotation of the hub which may cause a loose fit or unwanted displacement of the friction material.